1. Field of the Invention
The present invention relates to a radiation image pickup apparatus, a radiation image pickup system, a control method of the radiation image pickup apparatus, and a program for allowing a computer to execute the control method. More particularly, the invention relates to a radiation image pickup apparatus having a sensor array constructed by two-dimensionally arranging pixels each including: a conversion element for converting a radiation from an object into an electric signal; and a transfer switching element for transferring the electric signal to an outside.
2. Description of the Related Art
In recent years, there has been known a radiation image pickup apparatus of flat panel type using a sensor array constructed by two-dimensionally arranging pixels each constructed by: a conversion element for converting a radiation into signal charges (electric signal); and a switching element such as a TFT or the like for transferring the electric signal to an outside. In such a flat panel type radiation image pickup apparatus, each of the conversion element and the switching element is made of a material such as amorphous silicon or polysilicon formed as a film on a glass substrate. In the radiation image pickup apparatus, generally, by performing matrix-driving using the switching elements such as TFTs or the like, the signal charges converted by the conversion elements are transferred to a reading circuit unit and read out.
The conventional radiation image pickup apparatus has pixels each including: a photodiode made of amorphous silicon as a conversion element; and a thin film transistor (TFT) as a switching element. The device has a sensor array constructed by two-dimensionally arranging those pixels and performs the matrix-driving. A bias voltage is applied from a power source to a common electrode side of the photodiode of each pixel through a bias line.
The conventional radiation image pickup apparatus in which the area sensor array constructed by two-dimensionally arranging the pixels each having the photodiode and the switching element is read out by the matrix-driving has simply been described above. The radiation image pickup apparatus with such a construction in which the area sensor array is read out by the matrix-driving has been disclosed in, for example, U.S. Pat. No. 6,330,303.
In the conventional radiation image pickup apparatus, there is a case where a technique called “pixel binning” in which the pixels (of a plurality of rows) connected to a same drive wiring are grouped and signals of the group pixels are added and read out is used. It is an object of the pixel adding to accomplish the improvement of a reading speed, adjustment of resolution, an increase in signal amount, and the like. The embodiment about the pixel binning in the horizontal scanning direction has also been disclosed in U.S. Pat. No. 6,330,303.